if i understand correctly its going to pull beer from the beer out- in this case your floating dip tube- and then cycle it through the carb chamber and then push it back into the keg via the gas port. the problem i see with this is that in theory its possible that the floating dip tube takes beer from the top of the keg, it goes into the carb loop, and then gets shot back down the gas port right to the top of the keg/beer... where the floating diptube is pulling beer to go on the carb loop.
basically, it wouldnt get the thorough mixing that you'd see if you pulled beer from the bottom of the keg and then returned it to the top of the keg.
how badly this would affect the carbing process i have no idea. but my hunch tells me it could be an issue and you might need to run it significantly longer to make sure you get good mixing.
just a hunch but generally speaking you want good mixing in these situtations.
What if you laid the keg on it's side when carb'ing?
I am looking to get a quickcarb and have the same concerns on carb'ing with a floating diptube - before i order the quickcarb
It did work for me with the floating dip tube. It did take slightly longer, but there seems to be enough turbulence with the return being forced back into the keg. Inversion would be better than on the side. It would need to be braced to be inverted. The quick carb works well.